I had a lot of fun doing last year’s AMA and am excited to come back for another round of questions about everything from philanthropy to technology to how to lose a chess match in less than 90 seconds (http://www.youtube.com/watch?v=84NwnSltHFo). (Step 1: Play the world champion. There is no step 2.)

Playing Bridge is a pretty old fashioned thing in a way that I really like. I was watching my daughter ride horses this weekend and that is also a bit old fashioned but fun. I do the dishes every night - other people volunteer but I like the way I do it.

Wow. That is a nice thing to ask. I wish the debate about education would focus on helping teachers improve and what we know about that. Right now it is caught up in state versus federal and testing versus no-testing. In general politics needs to focus on the problems rather than attacking the other side. Asian countries are helping their teachers improve and the impact is huge.

No I don't. Other people think about that but I wouldn't want to extend my last few years unless that is happening for most people.

Q:

I am going to hit you with a tough one. What is the worst case that you know of where your philanthropy backfired? Here I mean the worst party possible benefitted from the gift. I am curious because I think there are important lessons to be learned from these kinds of stories for myself and others passionate about giving to the people who need it most .

A lot of our failures have been backing science that didn't work out. One thing that is tough is when you think the government will take over something you start but they don't - we had that with a school lunch program. It might have been better if we hadn't done it.

This is a sensitive topic. The idea was that men don't like the current design so perhaps something they would be more open to would allow for less HIV transmission. We still haven't gotten the results. One grantee is using carbon nanotubes to reduce the thickness,

Q:

Hey Bill, if you didn't go into computers and later found Microsoft, what do you think you would be doing?

The greatest tragedy is kids who die or never get enough food to develop physically or mentally to achieve their potential. We need vaccines and nutrition to solve this. We are making progress but not fast enough.

We need low cost energy that is totally reliable. Most renewables will require storage which is expensive to do this. Nuclear will make a contribution if we can make it safer, cheaper and deal with waste better. Terrapower has a design (on paper) that addresses all of these issues so now we are talking to countries about building it. It is a 4th generation reactor design that uses depleted uranium.

Q:

How do you deal with the anti-vaccination sentiment that seems to be growing in our society? Have you ever found yourself justifying your efforts to reduce polio?

(I'd like to give you an enormous thank you from myself personally. Thank you!!)

Education would be the top issue since it is key to individual opportunity and to the country as a whole and we are not doing as well as other countries. After that I would say immigration since the injustice of the current system is incredible.

We are very close. India just went 3 years with no cases. Pakistan is our toughest location right now because some parts of the Taliban have not allowed vaccinators to come in and have even attacked vaccinators. We are hopeful this will get resolved since no one wants their kid to be paralyzed. I spend a lot of time making sure the polio campaign is doing the best it can. We have great computer models that help guide our activities.

Just creating an innovative company is a huge contribution to the world. During my 20's and 30's that was all I focused on. Ideally people can start to mix in some philanthropy like Mark Zuckerberg has early in his career. I have enjoyed talking to some of the Valley entrepreneurs about this and I am impressed and how early they are thinking about giving back - much earlier than I did.

Q:

What is your most expensive guilty pleasure purchase?

EDIT: I left for class and came back to see that Bill Gates answered my question and CNET decided to make it a headline. I am so starstruck right now.

I am not a huge gamer. My son knows a LOT more than I do about what is cool on Xbox. I played Halo but the sports games that the whole family can use are the things I use the most. I threw the javelin very very far!

Q:

Bill,

Nuclear is notoriously expensive. How do you make sure that you manage/pick people to manage Terrapower so that it financially succeeds by building a product which makes money--and doesn't just make a dream plant?

Right now I know that Terrapower is looking at both sodium, and molten salt on the side, as a heat transfer fluid--why bridge out to so many technologies? Why not maintain a narrow focus?

Lastly, sodium plants have notoriously had issues over the history of nuclear power--both safety and cost wise--what is being done at Terrapower to make sure history isn't repeated?

I work on Molten Salts at U-Wisconsin Madison where I do a bunch of salt chemistry, which involves pushing hot salt through pipes/tubes at temperatures very similar to what Terrapower wants to run at. I'll be giving you guys a call when I get my PhD next December.

Terrapower is like most fast reactors which use Sodium cooling. We tried to stick to proven approaches wherever we could. There have been about 10 Fast Reactors. By using this approach we have no fuel problems and very limited waste generation. Most important is the inherent safety - no human involvement for shut down.

Q:

Hey Bill,

I'm actually an intern at Microsoft right now. How will your time be divided up between the foundation and Microsoft now that the CEO has asked you to step up. Also, could you host a talk for the interns. We'd love to hear about your work at the foundation and your thoughts on the future of tech.

Well Smil keeps writing great books like Made in the USA and Making the Modern World: Materials and Dematerialization. Paul Farmer has 3 books recently - to Repair the World is very accessible. In the Company of the Poor is a harder read but also good. www.gatesnotes.com tracks my reading closely. (http://www.thegatesnotes.com/books)

Q:

On ways to get funding and AID to developing countries: What are your thoughts on direct cash transfers like Give Directly? So instead of tying up aid into a potentially bureaucratic mess of requirements, just give cash to families and let them work out what they will do with the money.

Do you envision a bigger buy in by other Philanthropists for this type of work if the numbers look promising (they already do).

I favor improving the health of a country to enable them to be self-sufficient. I will be interested to see how cash transfer works out - in some cases like helping someone pay a school fee it could be catalytic. Our focus is health and agriculture which can transform a country. As long as kids don't have enough nutrition a country won't be able to support itself.

Q:

First of all, thanks for doing the AMA. And congrats to you on your spanking-new CEO.

My questions:

1) How does Mr. Nadella's vision differ from yours and Mr Ballmer's?

2) A couple of articles I read recently mentioned that the board is going to be putting pressure on the new CEO to exit the devices business and focus more sharply on enterprise customers. Your thoughts on that? If it means anything, I am a huge fan of the Surface. Can't afford one, but I have used the first one . Hugely impressed.

3) Also, this is pertinent to where I live -- India. A few people have a somewhat negative impression of the work that the B&MGF is doing; specifically, they claim it has an agenda to push products manufactured by American drug companies. Would you like to respond to that?

Satya is taking a fresh view of where Microsoft is - strengths and weaknesses. A new person gets to step back and change the focus in some ways. He is off to a great start.

In terms of the Foundation we fund vaccines that save childrens lives. The majority of those are made in India. In fact ironically India makes a lot of vaccines that are used in other countries but not in India. The Foundation is not trying to help anyone make money - simply to reduce the number of children who die from things like diarrhea and pneumonia.

Q:

Hi Bill! What is your favorite project you have ever worked on at Microsoft?

The Windows project which required a lot of patience was great. Office was also great. Together they defined the big success of the 1990s for Microsoft. Office connected to the cloud has a LOT of potential and we are off to a good start. Cloud Storage needs to be a lot richer though.

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